From nobody Sun Feb 8 07:58:57 2026 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.4]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 6CA7C2236F8; Tue, 3 Jun 2025 08:33:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.4 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748939636; cv=none; b=W4beeeSL7WaJqy7exCbFHVGFrb/tHR5mS638vlrWzHVBYmOtxjXoU1bhoDE+l9uBOhqqg1qqjHVulNaWiHjQtnFD1PKhV7CA8l60pAiks2QITjI8WkR7V1h/5QSz5ZR4yyDNdab0NaSLAsCPvsyC3Dw6okyaCG52TIWkFULCnuQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748939636; c=relaxed/simple; bh=jWw3s1a/AY/y1xwQIxxaCgV83PdUz2ciIda4uyzidXY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=oFOVUbZMVMQA2odzWPB3KJd1f/aRD8QmUqNik5X6q1ubDin5orFFNUun/tJEStKanGeEBnPRN947i5iNsYH/ek8fkE1JJrFcSYJkAj6B8OGsAuj01PFrH29dlz+kS1J/A6USKEjO62iOc4OMLLfj+HUOkrL2RxSN0xN3QfJETtQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=JCQGZjze; arc=none smtp.client-ip=220.197.31.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="JCQGZjze" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=dD eyhuFFoQ6/K4lWQy4ZVtm1IyFV5jCQTLNwpE/GG9Q=; b=JCQGZjzePj0jp5Xa0n ico3hqH9ZBTeITHXcyHIxUHZn2YONjhOmLYD7P1ffEXen/GE4fm8SQGKU84fCVAS 3sRChrT6hWoEQAWo/JhwYpD5zgu5eyAzyC8NOkSGGDgs9ZfvDn/G8sueHW1FUGYc 1Ra9VAHpbMYJ+UKPcsVnsluLI= Received: from localhost.localdomain (unknown []) by gzga-smtp-mtada-g0-4 (Coremail) with SMTP id _____wDXr+lBsz5oOoiAFw--.27977S4; Tue, 03 Jun 2025 16:33:17 +0800 (CST) From: David Wang <00107082@163.com> To: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, mingo@kernel.org, yeoreum.yun@arm.com, leo.yan@arm.com Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, David Wang <00107082@163.com> Subject: [PATCH v2] perf/core: restore __perf_remove_from_context when DETACH_EXIT not set Date: Tue, 3 Jun 2025 16:33:04 +0800 Message-Id: <20250603083304.34132-1-00107082@163.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20250603032651.3988-1-00107082@163.com> References: <20250603032651.3988-1-00107082@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wDXr+lBsz5oOoiAFw--.27977S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7AF4ftw15uFy3Xw4kAF1DWrg_yoW5JF4kpw s7CrnxK3y0q34qvw4ayr1kWwn8Cw4kJFZ0q3WDKw13XFWrXrW5XF1xKFW3Zrs0yr92qa47 tw4093ZrW3yqka7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0pREoGPUUUUU= X-CM-SenderInfo: qqqrilqqysqiywtou0bp/xtbB0gBhqmg+n-RC7QAJsC Content-Type: text/plain; charset="utf-8" commit a3c3c66670ce ("perf/core: Fix child_total_time_enabled accounting bug at task exit") made changes to __perf_remove_from_context() to coordinate its changes with perf_event_exit_event(), but the change are unconditional, it impacts callpaths to __perf_remove_from_context() other than from perf_event_exit_event(). One of the impact is to cgroup, which is not properly handled and would cause kernel panic with high probalibity during reboot on some system[1]. To confine the side effects, make the changes to __perf_remove_from_context() conditional, restore to its previous state except when DETACH_EXIT is set. Closes: https://lore.kernel.org/lkml/20250601173603.3920-1-00107082@163.com= / [1] Fixes: a3c3c66670ce ("perf/core: Fix child_total_time_enabled accounting bu= g at task exit") Signed-off-by: David Wang <00107082@163.com> --- Changes: Address yeoreum.yun@arm.com's concern about missing cgroup event. --- kernel/events/core.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 95e703891b24..e2c0f34b0789 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2466,7 +2466,7 @@ __perf_remove_from_context(struct perf_event *event, void *info) { struct perf_event_pmu_context *pmu_ctx =3D event->pmu_ctx; - enum perf_event_state state =3D PERF_EVENT_STATE_OFF; + enum perf_event_state exit_state =3D PERF_EVENT_STATE_EXIT; unsigned long flags =3D (unsigned long)info; =20 ctx_time_update(cpuctx, ctx); @@ -2475,19 +2475,20 @@ __perf_remove_from_context(struct perf_event *event, * Ensure event_sched_out() switches to OFF, at the very least * this avoids raising perf_pending_task() at this time. */ - if (flags & DETACH_EXIT) - state =3D PERF_EVENT_STATE_EXIT; if (flags & DETACH_DEAD) { event->pending_disable =3D 1; - state =3D PERF_EVENT_STATE_DEAD; + exit_state =3D PERF_EVENT_STATE_DEAD; } event_sched_out(event, ctx); - perf_event_set_state(event, min(event->state, state)); if (flags & DETACH_GROUP) perf_group_detach(event); if (flags & DETACH_CHILD) perf_child_detach(event); list_del_event(event, ctx); + if (flags & DETACH_EXIT) + perf_event_set_state(event, min(event->state, exit_state)); + if (flags & DETACH_DEAD) + event->state =3D PERF_EVENT_STATE_DEAD; =20 if (!pmu_ctx->nr_events) { pmu_ctx->rotate_necessary =3D 0; --=20 2.39.2